chore(agent): move docker entrypoint script to scripts/

Relocate agent-entrypoint.sh from docker/ to scripts/ so operational
shell scripts live in one directory and update Dockerfile.agent copy path.

scripts/agent-entrypoint.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+set -eu
+
+RUNTIME_USER="openflare"
+AGENT_BIN="/usr/local/bin/openflare-agent"
+
+fix_runtime_ownership() {
+  for target in /data /etc/openflare; do
+    if [ -d "$target" ]; then
+      chown -R "${RUNTIME_USER}:${RUNTIME_USER}" "$target" 2>/dev/null || true
+      chmod -R u+rwX,g+rX "$target" 2>/dev/null || true
+    fi
+  done
+}
+
+if [ "$(id -u)" -eq 0 ]; then
+  fix_runtime_ownership
+  exec su-exec "${RUNTIME_USER}" "${AGENT_BIN}" "$@"
+fi
+
+exec "${AGENT_BIN}" "$@"